Nine Engine Odors and the Problems they Represent

Your nose can play detective if you notice unusual odors coming from your engine. Each smell can signify a different problem. This guide can help you identify what your nose is telling you about your vehicle.

1. The smell of exhaust or fumes could be an exhaust leak. If the exhaust enters the car and raises the carbon monoxide levels, it could be dangerous for anyone inside the vehicle. You should stop driving, roll down the windows, and have a mechanic look at your vehicle.

2. The smell of burning oil or acrid smoke could be an oil leak. Oil might be leaking if the oil was recently changed and a drain plug wasn’t replaced properly or a filter wasn’t correctly attached. Oil can also leak due to a bad seal or gasket. Leaking oil can be dangerous as any oil that hits the exhaust could cause a fire. It’s also dangerous to the engine of your vehicle, since a low level of oil could cause severe damage to your engine. If you smell oil, you should have your car inspected by a licensed mechanic.

3. The smell of gas might be a gas leak. Vehicles over 50 years old might have a lingering odor of gasoline after the engine has been turned off. Any other vehicle, however, should not. If you start to smell gasoline, have your vehicle towed to a mechanic. Fuel leaking in the engine or near the exhaust line could start a fire.

4. The smell of burning plastic might be a short circuit in the wiring. Best case scenario, the burning plastic smell is from a piece of litter that has melted on the exhaust of your vehicle. Worst case scenario, however, could be the insulation over wires in your vehicle melting away and exposing the wires, which can cause a short and start a fire. Locate the source of the smell, and if you can’t, take your vehicle in to be looked at.

5. The smell of rotten eggs might be the catalytic converter. If the air-to-fuel ratio in your vehicle becomes imbalanced, it will create a sulfur smell while the unburned fuel clogs the catalytic converter. If it is caught early enough, the catalytic converter can be saved, so do not hesitate to take your vehicle in if you begin smelling rotten eggs.

6. The smell of burnt carpet might be the brake pads or rotors. Recently replaced brake pads might give an odor of burnt carpet, but if you haven’t had your brakes serviced recently, starting to smell burnt carpet is not a good sign. The brake pads might be too thin, the brake calipers might be sticking or dragging, or the rotors might be overheating. Either way, your ability to slow and stop your vehicle is potentially compromised, and you will want to have your brakes inspected as soon as you can. Until you get to a mechanic, pump your brakes instead of riding down on them.

7. The smell of something sweet or fruity could be coolant. The coolant your engine uses to prevent overheating has a sweet smell. If you smell it when you are using your vehicle, it may indicate a leak, which would not leave enough for your engine to be properly cooled. Driving could damage your engine because it does not have a way to cool itself. Have your vehicle towed to a trained mechanic to inspect the engine.

8. The smell of burnt rubber could be misaligned belts or overheated rubber. If you notice a burnt rubber smell, let your car cool down then look under the hood. You might notice an engine belt that has slipped off its pulleys, or the pulley may be malfunctioning and shredding the belt. A rubber hose might also be coming into contact with a belt, and the friction might be melting the hose. You should be able to identify the source of the burning rubber under the hood. If you need help, find a trusted mechanic.

9. The smell of mildew or mold might be the air conditioning. Ideally, your air conditioning would pull moisture from the air and drain the extracted water behind the dashboard. It is possible, however, for the drain to get blocked by leaves or paper, which leaves the water stuck and it eventually molds. Air conditioning that is not run regularly is also susceptible to mold-spawning moisture building up in the ducts while it is not being used. Have any mold or mildew smells inspected, as it can be a costly problem.

Using your nose you can hopefully catch problems in your vehicle before they become larger problems. In addition to being a branded title dealership, we also have a full service mechanic and collision center. If you are in the Salt Lake City, Utah area and experience any of these smells coming from your car, we would love to help you solve the mystery and return your car to its original odor-free condition.